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      <a id="pvsmooth"></a>
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      <a id="Indexpvsmooth" class="indexterm"></a>
      <div class="refnamediv">
        <h2>
          <span class="refentrytitle">pvsmooth</span>
        </h2>
        <p>pvsmooth — 
      Smooth the amplitude and frequency time functions of a pv stream using parallel 1st order
      lowpass IIR filters with time-varying cutoff frequency. 
    </p>
      </div>
      <div class="refsect1">
        <a id="idp139544192"></a>
        <h2>Description</h2>
        <p>
      Smooth the amplitude and frequency time functions of a pv stream using a 1st order
      lowpass IIR with time-varying cutoff frequency. This opcode uses the same filter 
      as the <span class="emphasis"><em>tone</em></span> opcode, but this time acting separately on the amplitude and frequency
      time functions that make up a pv stream. The cutoff frequency parameter runs at the
      control-rate, but unlike <span class="emphasis"><em>tone</em></span> and <span class="emphasis"><em>tonek</em></span>, it is not specified in Hz, but as fractions
      of 1/2 frame-rate (actually the pv stream sampling rate), which is easier to
      understand. This means that the highest cutoff frequency is 1 and the lowest 0; the lower
      the frequency the smoother the functions and more pronounced the effect will be. 
    </p>
        <p>
      These are filters applied to control signals so the effect is basically blurring the spectral evolution. The effects produced are more or less similar to <span class="emphasis"><em>pvsblur</em></span>, but with two important
      differences: 1.smoothing of amplitudes and frequencies use separate sets of filters; and 2. there is
      no increase in computational cost when higher amounts of 'blurring' (smoothing) are desired.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp139548448"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">fsig <span class="command"><strong>pvsmooth</strong></span> fsigin, kacf, kfcf</pre>
      </div>
      <div class="refsect1">
        <a id="idp139550592"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>fsig</em></span> -- output pv stream
    </p>
        <p>
      <span class="emphasis"><em>fsigin</em></span> -- input pv stream.
    </p>
        <p>
      <span class="emphasis"><em>kacf</em></span> -- amount of cutoff frequency for amplitude function filtering, between 0 and 1,
      in fractions of 1/2 frame-rate.
    </p>
        <p>
      <span class="emphasis"><em>kfcf</em></span> -- amount of cutoff frequency for frequency function filtering, between 0 and 1,
      in fractions of 1/2 frame-rate.
    </p>
        <div class="warning" style="margin-left: 0.5in; margin-right: 0.5in;">
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              </td>
              <th align="left">Warning</th>
            </tr>
            <tr>
              <td align="left" valign="top">
                <p>
        It is unsafe to use the same f-variable for both input and output of pvs opcodes. Using the same one might lead to undefined behavior on some opcodes. Use a different one on the left and right sides of the opcode.
      </p>
              </td>
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      <div class="refsect1">
        <a id="idp139555984"></a>
        <h2>Examples</h2>
        <p>
      Here is an example of the pvsmooth opcode. It uses the file <a class="ulink" href="examples/pvsmooth.csd" target="_top"><em class="citetitle">pvsmooth.csd</em></a>.
      </p>
        <div class="example">
          <a id="idp139557760"></a>
          <p class="title">
            <strong>Example 707. Example of the pvsmooth opcode.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
-odac  <span class="comment">;;;realtime audio out</span>
<span class="comment">;-iadc    ;;;uncomment -iadc if realtime audio input is needed too</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o pvsmooth.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 32
<span class="ohdr">nchnls</span> <span class="op">=</span> 2
<span class="ohdr">0dbfs</span>  <span class="op">=</span> 1

<span class="oblock">instr</span> 1

kacf <span class="op">=</span> p4
kfcf <span class="op">=</span> p5
asig <span class="opc">soundin</span> "fox.wav"
fsig <span class="opc">pvsanal</span> asig, 1024, 256, 1024, 1	<span class="comment">; analyse it</span>
ftps <span class="opc">pvsmooth</span> fsig, kacf, kfcf
atps <span class="opc">pvsynth</span> ftps			<span class="comment">; synthesise it                      </span>
     <span class="opc">outs</span> atps<span class="op">*</span>3, atps<span class="op">*</span>3

<span class="oblock">endin</span>
<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>
<span class="comment">;       amp  freq </span>
<span class="stamnt">i</span> 1 0 3 0.01 0.01	<span class="comment">;smooth amplitude and frequency with cutoff frequency of filter at 1% of 1/2 frame-rate (ca 0.86 Hz)</span>
<span class="stamnt">i</span> 1 + 3  1   0.01	<span class="comment">;no smoothing on amplitude, but frequency with cf at 1% of 1/2 frame-rate (ca 0.86 Hz)</span>
<span class="stamnt">i</span> 1 + 10 .001  1	<span class="comment">;smooth amplitude with cf at 0.1% of 1/2 frame-rate (ca 0.086 Hz)</span>
			<span class="comment">;and no smoothing of frequency</span>
<span class="stamnt">e</span>
<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
          </div>
        </div>
        <p><br class="example-break" />
    </p>
        <p>
     The formula for calculating the cutoff frequency of the filter: frame rate / hopsize = new frame starts per second (in Hz), then the percentage of half the framerate.
     For example, looking at the first note in the example, the frame rate is 44100 / 256 = 172,265625 Hz (= 172 new frame starts per 
second). half of the frame rate is about 86 Hz, and one percent of this is 0.86 Hz.
    </p>
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      <div class="refsect1">
        <a id="idp139562848"></a>
        <h2>Credits</h2>
        <p>
      </p>
        <table border="0" summary="Simple list" class="simplelist">
          <tr>
            <td>Author: Victor Lazzarini</td>
          </tr>
          <tr>
            <td>May 2006 </td>
          </tr>
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        <p>
    </p>
        <p>New plugin in version 5</p>
        <p>May 2006.</p>
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